Internal-combustion engine and method of operating same.



E. THOMSON.

INTERNAL COMBUSTION ENGINE AND METHOD OF OPERATING SAME.

- APPLICATION FILED MAR. 29, 1906, 1,096,405.

Patented May 12, 1914.

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E. THOMSON.

INTERNAL COMBUSTION ENGINE AND METHOD OF OPERATING SAME.

APPLICATION FILED MAR. 29, 1906.

Patented May 12, 1914.

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ELIHU THOMSON, OF SWAMPSCOTT, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

INTERNAL-COMBUSTION ENGINE AND METHOD OF OPERATING SAME.

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Specification of Letters Patent.

Patented May 12, 1914.

Application filed March 29, 1906. Serial No. 308,670.

T 0 all whom it may concern Be it known that I, ELIHU THOMSON, a citizen of the United States, residing at Swampscott, in the county of Essex and State ofMassachusetts, have invented certain new and useful Improvements in Internal-Combustion Engines and Methods of Operating the Same, of which the followingiis a specification.

My invention relates to an internal combustion engine of the type in which the fuel charges are self-ignited, and its ob ject is to combine the advantage of selfignition, as in the Diesel engine, with that of combustion of the charges at a comparatively high initial pressure without the necessity of the objectionably high compression essential in the Diesel cycle. The pressure of compression in the Diesel engine is about 550 lbs. per square inch, and the heat developed by compression of the air to this extent is utilized to fire the fuel when injected into the compressed air. To operate with such a high compression requires very exacting workmanship in the construction of the engine, and at the best considerable pistonring trouble, or leakage, is sooner or later experienced, thus aflecting the efiiciency. Furthermore, to obtainthe proper fly-wheel effect the operating parts have to be large and heavy, so that as a consequence, the size ofthe engine compared with the output is disproportionately large. With the present invention, .1 overcome these objections by employing a much lower compression which, :for instance, may be from 250 to 300 lbs. per square inch. The piston on its instroke is adaptedto compress the air charge to a pressure of about 150 lbs. sure is'also established in a supplemental combustion. or pro-ignition. chamber arranged at the head of'the piston cylinder and in open communication with the combustion chamber or clearance of the latter.

Into this chamber, whose walls are initially.

heated'by applying a torch-flame thereto, a charge-of fuel is in ected,- WlllCh vaporizes and-mixes withair entering from the cylinder so that itselfdgnites at a definite point in the compression'stroke. The flaming gases rush into the cylinder and mix This pres-.

stituting the air charge is largely in excess.

of that consumed by the initial or supplemental eombustion, so that the proper proportion of oxygen will be present to produce complete and economical combustion of the main fuel charge. The main fuel charge is injected at or a little after the time the piston passes or has passed the inner dead center. An engine operating according to this method has an indicator diagram which from the beginning of the compression stroke shows a gradual rise in pressure in anadiabatic curve to about 150 lbs, an abrupt increase at the time of'comb'ustion of the supplemental charge to about 250 lbs., and a continued increase owing to combustion, and other compression to approximately 300 lbs. At this point the main fuel charge is injected and fired, showing a rise to maximum pressure. On the power stroke the diagram shows a sustained pressure over the first portion of the stroke during the continuation of the combustion and thereaftera falling off to the end of'the stroke.

The invention is applicable to engines having one, two or more cylinders and operating on either the two-stroke or the four stroke cycle, the fuel supply system being organized in each case to supply the fuel charge at the proper time. In the fourstroke engine the scavenging-would be done in the usual 1nannerduring the in-stroke succeeding the power stroke, whereas in the two-stroke engine the cylinder would be scavenged by pumping fresh air into the same during-the exhaust period, the residual air constituting the air charge to be compressed during the in-stroke.

The supplemental fuel charge is preferably so proportioned that the impulse resulting from the combustion will be such as to keep the engine operating while running light. By means of a suitable loadresponsive device the main fuel supply may be cut into or out of operation, or the fuel charge quantitatively varied from time to time to meet changing conditions of operation. The supplemental fuel supply is maintained substantially constant so that the combustion in the supplemental combustion chamber continues uninterrupted. Besides keeping the engine Operating this ignition in the supplemental chamber serves to keep the walls hot and hence the engine ready for regular duty at all times.

i For a more detailed understanding of the invention, attention is directed to the following description taken with the accompanying drawings, and to the features of .novelty pointed out in the claims appended hereto.

In the accompanying drawings which illustrate one of the embodiments of the invention, Figure 1 is a longitudinal section of an engine of the four-cycle type with the improvements applied thereto; Fig. 2 is a top view of the engine; and Fig. 3 'is a detail section of the cylinder head and attached parts.

Referring to the drawings, 1 represents a cylinder of the water-jacketed construction having a clearance or combustion chamber 2, and in which reciprocates the piston 3. The piston is'connected to a crank-shaft 4 which carries'a fly-wheel 5, by means of the connecting rod 6. Arranged at the head of the cylinder is a hollow, spherical, supplemental combustion chamber 7 having free communication with the clearance or combustion chamber 2. This chamber 7 is un'jacketed so that the walls thereof may be initially heated by a torch and kept heated by the successive combustion within it to a temperature sufficient to spontaneously ignite fuel charges delivered thereto.

Since the engine is of the four-cycle type, air inlet and exhaust conduits 8 .and 9, respectively (Fig. 2) are arranged at the head of the cylinder and each is controlled by a mechanically actuated valve 10, only the ex haust valve being shown in the sectional figure. Also arranged at the head of the cylinder is a spraying device 11 which sprays themain charge of fuel into the cylinder or combustion chamber thereof. Fuel is supplied to the supplemental chamber through a supply pipe 12 which terminates in a sprayer 12 and to the main sprayer 11 through a supply pipe 13. source of supply may be employed but I prefer to use a pump 14 common to both supply pipes. The plunger 15 of the pump.

receives motion from a cam 16 arranged on a secondary or half-speed shaft 17 so thatthe pump delivers its charge every fourth stroke of the engine piston. The pump draws its supply from a suitable source through the suction pipe 18 contro-lled by the suction valve 19. Separate discharge valves20, 21 control res ectively, the supply pipes 12 and 13. he connection between the pipe 12 and the pump is arranged at some distance from the head of the pump cylinder with which headthe pipe 13 con- Any suitable nects so that during the first part of the discharge from the pump, fuel is delivered to the supplemental combustion chamber, and during the remaining portion of the stroke, I to the main sprayer 11 the object of which relation is more fully set forth hereinafter.

The suction stroke of the pump is performed by a compression spring 22 arranged between abutments 23, the discharge stroke compressing the spring so that the piston is withdrawn when the cam 16 passes from under the plunger actuator or push rod 24. In order that the pressure in the main supply pipe 13 may not become excessive, a by-pass 25 is provided which is controlled by a release valve 26.

For spraying the fuel into the clearance or combustion chamber 2, air under com pression is employed but other gases might be used if desired, the essential function of the air or gas being merely to atomize or spray the fuel and convey it to the cylinder.

This air is supplied by a compound pump having a low pressure piston and cylinder 27 and a high pressure piston and cylinder 28. The pump piston is operated from an eccentric 29 on the crankshaft by a crosshead and connecting rod connections 30. The low pressure plunger draws its supply through a suction Valve 31 and discharges into a low pressure chamber 32 through the valve 33. The high pressure plunger draws its supply from the chamber 32 through a suction valve 34 and discharges into a high pressure reservoir 35 through the delivery valve 36. The fuel and air supplies are delivered to the sprayer through conduits 37 and 38, respectively, which are controlled by needle valves 39 and. 40. The sprayer comprises a plurality of superposed perforated gauze diaphragms 41 through which the fuel and air are discharged, the same serving to mix the two and also to prevent back firing from the combustion chamber 2. The fuel and air pumps are of such size as to deliver the desired amount of fuel and air at a pressure of about 300 lbs. to the square inch, such pressure being that attained in the combustion chamber 2 at the time the main fuel discharge is injected. At the outer end of each needle valve is a yoke 42 in which en gages the free end of a lever 43, Figs. 2 and 3. The levers 43 are fulcrumed on the standroeenoa lift of the valves, the cam sleeve 48 is ad justa ble along the cam shaft 46 to which it is feathered so as to present difierent portions ofthecams to-the rollers 49 of the valve actuating levers 43 in a well known man ner; For-this purpose a-camshipper or controller 53 is provided, comprising a lever which is ful'crumed on the standard 44 at 54am] engages at its inner end the collar 55 attached to the cam sleeve. On the controller is arranged a latch 56 that engages with the notched sector 57 and holds the controller in any desired position.

The fuel and air pumps are adapted to deliver suflicient fuel and air for the maximum demand. l/Vhen, however, the needle valves are so adjusted as to permit less than the-maximumdischarge fromthe pumps to be delivered to the engine, the surplus of fuel and 'air-is-by-passed. The fuel is bypassed through the valve 26, Fig, l, and

pipe. 25, and the air is by-passed through the passage or conduit 58, between the high and low pressure chambers 32 and 35. The by passis controlled by a regulator or governing means which comprises a needle valve 59 attached=to a diaphragm 60. The diaphragm issubjected to the air pressure in the high pressure chamber 35 by means of the conduit 61 communicating with the bypass-58 and. the diaphragm containing chamber 62. The diaphragm is weighted by a spring 63- thatacts through the bell crank lever 64 to which'it'is attached. One arm of the lever impinges upon the outer end of the needle valve that extends through the wall of the diaphragm chamber. By this arrangementthe spring urges the valve against its seat: to close the by-pass while the diaphragm acts against. the tension of the spring when the air pressure exceeds a predetermined amount to open theby-pass. When the by-pass is opened the high pros sure pump discharges into the. high pressure chamber 35 and. the air passes therefrom through the by-pass back to the low ,pressure chamber. In order to prevent thepressure in thelow pressure chamber 32, due to the pump 27 from becoming excessive the suction valve 31 is adapted to be held open by means of a lever 65 linked to thebellthe opening of the by-passvalve 59 the suc- "tion valve 31 will be opened. Hence the low pressure pump draws-in air through the suction valve and discharges it again therethrough without delivering any to the low pressure chamber.

The speed of the engine is automatically controlled by means'of the centrifugal gov- A 65; ernor 66 arranged on the'half-speed shaft 17 which shifts the cam 16. By this means the stroke ofthe fuel pump and hence the quantity of fuel. delivered thereby to the engine cylinder will be automatically varied according to the demands. For simplicity the air charges are substantially constant,.

so that by varying the fuel charges the resulting combustible mixture will vary somewhat as to its richness to suit the demands for power The air inlet and exhaust valves 10 are both mechanically operated. A bell crank lever 67 for eachvalve is mounted on stand- .ards 68 extending from the head of the cylinider, Fig. 3.

The levers are periodically oscillated by cams 69 arranged on the cam :shaft46 which cause the ends 70 of the bellcrank levers to be depressed. so as to open ?the valves. The valves are closed by means of springs 71 arranged around the stems 72 landconfinedbetwcen a stationary abutment 73 and the movable abutment or head 74 on the upper ends of the stems. The cams for actuating the levers 67 are so related that the valves will open in proper sequence.

The operation isas follows: The walls of the supplemental combustion chamber are heated to the proper temperature by apply ing the torch thereto. The engine is next cranked so as to draw in a charge of air and to start the pumps. The fuel pump delivers first to the supplementary combustion chamber, simultaneously with the in-stroke of the engine piston. Air in the engine cylinder is thus'compressed and a portion thereof passes to the supplementary chamber and is carbureted by the fuel delivered thereto by the pump. By reason of the.heatcd walls of the chamber the fuel mixture spontaneously ignites, this taking place preferably slightly before the completion of the compression stroke. During the time the fuel is dis charging in the supplementary chamber the needle valve is closed so that the fuel pump is delivering only to the supplementary chamber. After the initial combustion, however, the needle valve is opened so that the pump on continuation of its discharge stroke, delivers fuel to the main sprayer 11. Simultaneously with the stroke of thefucl pump airunder ressure passes from the chamber 35 and is admitted to the main sprayer 11 in the proper amount to effectually spray the fuel into the flaming prod ucts of combustion that have in the meantime entered the main combustion chamber 2 from the supplementary chamber 7. This produces the power stroke. As the air pump is driven direct from the engine shaft, it will have two strokes compared to the one of the fuel pump so that the proper airpressure can be obtained in the chamber By suitably adjusting the cam sleeve 48 the main fuel charge can be delivered to the engine at the proper time and the period of pressed on the next in-stroke of the piston and the cycle of operation is repeated. In case the speed varles, due to load changes, the governor varies the amount of fuel delivered to the engine so that the power derived from combustion of the resultant mixture of air and fuel will be automatically changed in accordance with the demand.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represeht the best embodiment thereof; but I desire to have it understod that the apparatus shown is only illustrative, and that the invention can be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is,

1. The method of operating an internal combustion engine which consists in admitting air to the cylinder, compressing the air therein to a moderate degree, introducing into the cylinder burning gases and products of combustion under a pressure superior to the compression pressure during the later portion of the compression stroke to-raise the temperature of the compressed air charge to ignition value, and subsequently introducing a fuel charge into the cylinder at or near the inner end of the piston stroke which is ignited by the temperature of the gases contained therein.

2. The method of operating internal combustion engines, which consists in supplying air to the cylinder, compressing the air therein to a pressure less than that necessary for igniting the fuel chargeby the heat of compression, introducing flaming gases into the cylinder during the later portion of the compression stroke to increase the temperature and pressure of the contents of the cylinder, and subsequently introducing a fuel charge into the contents of the cylinder in the presence of said flaming gases so that the charge is ignited thereby.

3. The method of operating internal combustion engines having a combustion chamber connected with the interior of the engine cylinder, which comprises supplying air to the cylinder, compressing air in the chamber and cylinder to a pressure less than that necessary for igniting the fuel charge by the heat of compression, introducing fuel into the chamber from which the burning gases pass into the cylinder during'the compres sion stroke to increase the temperature and "pressure of the contents of the cylinder, and

subsequently introducing a fuel charge into the contents of the cylinder at or. near the completion of the compression stroke so that the charge is ignited by said burning gases.

t.- The method of operating internal combustion engines having a separate combustion chamber in open communication with the interior of the cylinder, which consists in supplying air to the cylinder and chamber, compressing air in the cylinder and chamber to a pressure substantially less than that necessary for igniting the fuel charge by the heat of compression, introducing fuel into the air in the chamber near the end of the compression stroke and igniting the contents of the chamber so that flaming gases pass from the chamber into the cylinder to increase the temperature- ,less than that required for igniting the fuel charge by the heat of compression, introduc ing flaming gases int-o the compressed air to increase the temperature and pressure of the contents of the cylinder, and subsequently spraying a fuel charge into the clearance space of the cylinder at or near the completion of the compression stroke by means of compressed air at a pressure higher than the pressure in the cylinder,

said charge being ignited'by the flaming gases.

6. The method of operating internal combustion engines having a heated retort or combustion chamber in constant and open communication with the working cylinder, which consists in compressing air unmixed wit-h fuel in the cylinder and chamber to a temperature below the igniting temperature of the fuel, feeding fuel'into the air in the combustion chamber where it is caused to ignite solely by contact with the hot walls thereof, and forcing fuel into the working cylinder against the compression pressure where it is ignited by the burning gases issuing from the combustion chamber.

' 7. The method of operating internal combustion engines having a combustion chamber connected with the. interior of the cylinder, which comprises supplying air to the cylinder, compressing air in the cylinder to a degree" less than that necessary for igniting the fuel charge by the heat of compression, igniting an explosive. mixture in the chamber during the later part of the compression stroke so that flaming gases pass from the chamber to the cylinder, and subsequently introducing a fuel charge into the cylinder at or near the inner limit of the movement of the piston, the charge being ignited by said flaming gases.

8. The method of operating internal combustion engines having a combustion chamber in open communication with the working'cylinder, which consists in introducing latter part of the compression stroke, igniting the contents of the chamber by means of the hot walls thereof, said contents passing into the work cylinder to raise the tem- .perature of the air therein and subsequently delivering a fuel charge into the cylinder adjacent the discharge of the combustion chamber to mingle with and be ignited by the hot gases discharged from said chamber.

9. The method of operating internal combustion engines having a combustion chamber in open communication with the engine cylinder, which comprises separate forcing air and a small amount of fuel into the chamber during the latter part of the compression stroke of the engine, igniting the mixture of air and fuel in the chamber, and subsequently forcing a fuel charge into the body of hot flaming gases delivered to the cylinder from the chamber.

10. The method of operating internal combustion engines having a heated retort or combustion chamber in constant and open communication with the working cylinder, which consists in compressing airunmixed with fuel in the 'cylinder and retort to such a pressure that its temperature is below the ignitin point of the fuel, delivering a charge 0 fuel to the retort where it mixes with the compressed air and is ignited as it enters by the hot walls of the retort, said charge being suificient to drive the engine when there is no load, and forcing fuel into the compressed air in the working cylinder where it is ignited by the hot gases issuing from the retort due to the earlier ignition.

11. The method of operating internal combustion engines having a combustion chamber communicating with the engine cylinder, which comprises igniting in the chamber a relatively fixed amount of explosive mixture, and introducin the flaming gases from the chamber into t e cylinder during the compression stroke and subsequently feeding a fuel charge into the cylinder to mingle with and be ignited by the flaming gases discharged from the chamber, said charge be ing proportioned to the load on the engine.

12. In an internal combustion engine, the combination of a cylinder having an air inlet and a clearance space, a piston in the cylinder which on an instroke compresses a charge of air in the cylinder and clearance space to a degree considerably below that necessary for igniting the fuel charge by the heat of compression, a combustion chamber" from chamber and passin raise the pressure and tempcratureof its contents, a spraying device arranged to supply fuel to the clearance space of the cylinder,

which flaming gases enter the cylinder, an open conduit between the cylinder and the chamber whereby compression is established in the latter during the compression stroke of the piston, means for injecting fuel into the compressed air in the chamber prior to the end of the compression stroke, the mixfuel and air lnto sald chamber during the ture being ignited by the hot walls of the into the cylinder to and means supplying air and liquid fuel to the spraying device to deliver a fuel charge to said space, the hot gases from the combustionchamber igniting the mixture in the cylinder to produce the power stroke.

13. In an internal combustioncnginc, the combination with a cylinder having an air inlet and a clearance space, of a piston which on an instroke compresses a charge of air in the cylinder and clearance space to a degree considerably below that necessary for igniting the fuel charge by the heat of compression, a combustion chamber communicating with the interior of the cylinder whose walls are heated by the combustion in the chamber so that they ignite fuel delivered to the chamber, said chamber discharging flaming gases into the cylinder for increasing the pressure and temperature of its contents, means for spraying fuel into the chamber prior to the end of the compression stroke to produce a body of flaming gases therein, a sprayer for spraying fuel into the cylinder, a source of fuel supply connected with the sprayer, a source of compressed air supply also connected with the sprayer, and means for opening communication between said sources and the sprayer at or near the inner end of the piston travel so that the mixture is fired by said flaming gases as the fuel is sprayed into the contents of the cylinder.

14. In an internal combustion engine, the combination of a cylinder having an air inlet and a clearance space, a piston which on an instroke compresses a charge of air in the cylinder and clearance space to a degree considerably below that necessary to ignite the fuel charge by the heat of compression, a combustion chamber whose Walls are heated by the'combustion therein so as to ignite the fuel delivered thereto and to deliver flaming gases to the cylinder for increasing the pressure and temperature of its contents, means for spraying fuel into the chamber near the end of the compression stroke to produce a body of flaminggases therein, a sprayer for spraying fuel into the cylinder, a source of fuel supply connected with the sprayer, a

sprayer at or near the inner end of the piston travel and after the flaming gases have entered the cylinder so that said gases fire the mixture as the fuel is sprayed into the contents of the cylinder.

15. In an internal combustion engine, the combination of a cylinder having an air inlet and a clearance space, a piston which on the instroke compresses a charge of air ii the cylinder and clearance space to a degre d to the sprayer, a governorfor the pump, an

air pump also driven by the engine which supplies air to the sprayer, separate valves for the fuel and air supplies, and means for opening. the valves at or near the inner limit of the piston. travel and after the flaming gases have entered the cylinder so that said gases will ignite the mixture as the fuel charge is sprayed into the contents of the cylinder. I

16. In an internal'combustion engine, the combination with a cylinder having an air inlet and a clearance space, of a piston which on the instroke compresses a charge of air in the cylinder and clearance space to a degree considerably below that necessary to ignite the fuel charge by the-heat of compression,-a combustion chamber whose walls' are heated by the combustion therein so as to ignite fuel delivered thereto and to deliver flaming gases to the cylinder to in crease the pressure and temperature of its contents, means for spraying fuel into the chamber near the end of the compression stroke, a sprayer -for spraying fuel lnto the contents of the cylinder after their temperature and pressure have been increased by said flaming gases, a pump driven by the engine which supplies fuel to the sprayer,

a governor for the fuel pump, an air pump also driven by the engine which supplies air to the sprayer, and agovernor for the air pump.

17. In an internal combustion engine, the

, combination with a cylinder having an ant inlet and a clearance space, ofa piston which on an instroke compresses a charge of air in the cylinder and clearance space to a degree considerably below that required for igniting the fuel charge by the heat of compression, a combustion chamber whose walls are heated by the combustion therein so as to ignite fuel delivered to the chamber and roaches to deliver flaming gases to the cylinder for increasing the pressure and temperature of its contents, a sprayer for spraying fuel into the chamber near the end of the compression stroke, a sprayer for'spraying fuel into the cylinder, a pump driven by the engine which supplies fuel to both sprayers, a speed responsive device which controls the delivery of fuel to the cylinder sprayer without'affecting the supply to the other sprayer, an air pump also driven by the engine which supplies air to the cylinder sprayer, a governor for the air pump which is controlled by the pressure of the'air delivered thereby, separate valves for the fuel and air supplies, and means for opening the valves while the piston is near the inner end of its travel and after the flaming gases have entered the cylinder so that said gases will, ignite the mixture as the fuel which is sprayed into the cylinder. r

18. In an internal combustion engine, the combination of a cylinder having a clearance space, a valved port through which air is admitted to the cylinder, a combustion chamber in permanent open communication with the clearance space, a piston in the cylinder which on. an instroke compresses air in the clearance spaceand the chamber to a degree considerably below that necessary for ignit ing the fuel charge by the heat of compres sion, means discharging fuel into the com pressed air in the chamber where it is ignited ting burning gases to the cylinder to raise the temperature of the air therein to a value above the igniting temperature of the fuel, a device for spraying fuel into the cylinder after the temperature of the air therein has been raised to ignition value, a pump driven by the engine for compressing air, a fuel pump driven by the engine, a speed go'vernor, means controlled by the governor for varying the eHect-ive delivery of the fuel pump, conduits for delivering air and fuel from the pumps to said device, and cam means driven by the engine that controls the action of said device and causes it to spray a fuel charge into the cylinder at or near the completion of the compression stroke 20. In an internal combustion. englne, the combination of a cylinder having a combustion chamber in open communication with the interior of the cylinder, means for su plyin air to the cylinder, a piston in t e cylin er that compresses the air. therein on an inward stroke, a device for spraying fuel into the cylinder, a pump driven by the engine for compressing air, a fuel pump, conduits for delivering air and fuel from the pumps to said devlce, a conduit for delivering fuel from the pump to the combustion chamber, means driven by the engin for actuating the fuel pump to deliver fue to the combustion chamber durin the latter portion of the compression stro e of said piston to be ignited therein by the walls of said chamber that are kept hot by the combustion of its contents, and cam means driven by the engine that controls the action of said device and causes it to spray a fuel charge into the cylinder at or near the con1- ELIHU THOMSON.

Witnesses:

JOHN A. MCMANUS, J r., HENRY O. \VEsTENnAnr. 

